[clang][ast] Inner struct with same name missing from AST layout #155936
Description
We have some tests failing after #147835 (plus fixes) that use this as the test snippet for their matcher:
struct Foo {
struct A {
struct Foo {};
};
};Before: https://compiler-explorer.com/z/7e6836e6G
TranslationUnitDecl
`-CXXRecordDecl <line:1:1, line:5:1> line:1:8 struct Foo definition
|-DefinitionData pass_in_registers empty aggregate standard_layout trivially_copyable pod trivial literal has_constexpr_non_copy_move_ctor can_const_default_init
| |-DefaultConstructor exists trivial constexpr needs_implicit defaulted_is_constexpr
| |-CopyConstructor simple trivial has_const_param needs_implicit implicit_has_const_param
| |-MoveConstructor exists simple trivial needs_implicit
| |-CopyAssignment simple trivial has_const_param needs_implicit implicit_has_const_param
| |-MoveAssignment exists simple trivial needs_implicit
| `-Destructor simple irrelevant trivial needs_implicit
|-CXXRecordDecl <col:1, col:8> col:8 implicit struct Foo
`-CXXRecordDecl <line:2:5, line:4:5> line:2:12 struct A definition
|-DefinitionData pass_in_registers empty aggregate standard_layout trivially_copyable pod trivial literal has_constexpr_non_copy_move_ctor can_const_default_init
| |-DefaultConstructor exists trivial constexpr needs_implicit defaulted_is_constexpr
| |-CopyConstructor simple trivial has_const_param needs_implicit implicit_has_const_param
| |-MoveConstructor exists simple trivial needs_implicit
| |-CopyAssignment simple trivial has_const_param needs_implicit implicit_has_const_param
| |-MoveAssignment exists simple trivial needs_implicit
| `-Destructor simple irrelevant trivial needs_implicit
|-CXXRecordDecl <col:5, col:12> col:12 implicit struct A
`-CXXRecordDecl <line:3:9, col:21> col:16 struct Foo definition
|-DefinitionData pass_in_registers empty aggregate standard_layout trivially_copyable pod trivial literal has_constexpr_non_copy_move_ctor can_const_default_init
| |-DefaultConstructor exists trivial constexpr needs_implicit defaulted_is_constexpr
| |-CopyConstructor simple trivial has_const_param needs_implicit implicit_has_const_param
| |-MoveConstructor exists simple trivial needs_implicit
| |-CopyAssignment simple trivial has_const_param needs_implicit implicit_has_const_param
| |-MoveAssignment exists simple trivial needs_implicit
| `-Destructor simple irrelevant trivial needs_implicit
`-CXXRecordDecl <col:9, col:16> col:16 implicit struct Foo
After: https://compiler-explorer.com/z/oeK8jaKh8
TranslationUnitDecl
`-CXXRecordDecl <line:1:1, line:5:1> line:1:8 struct Foo definition
|-DefinitionData pass_in_registers empty aggregate standard_layout trivially_copyable pod trivial literal has_constexpr_non_copy_move_ctor can_const_default_init
| |-DefaultConstructor exists trivial constexpr needs_implicit defaulted_is_constexpr
| |-CopyConstructor simple trivial has_const_param needs_implicit implicit_has_const_param
| |-MoveConstructor exists simple trivial needs_implicit
| |-CopyAssignment simple trivial has_const_param needs_implicit implicit_has_const_param
| |-MoveAssignment exists simple trivial needs_implicit
| `-Destructor simple irrelevant trivial needs_implicit
|-CXXRecordDecl <col:1, col:8> col:8 implicit struct Foo
`-CXXRecordDecl <line:2:5, line:4:5> line:2:12 struct A definition
|-DefinitionData pass_in_registers empty aggregate standard_layout trivially_copyable pod trivial literal has_constexpr_non_copy_move_ctor can_const_default_init
| |-DefaultConstructor exists trivial constexpr needs_implicit defaulted_is_constexpr
| |-CopyConstructor simple trivial has_const_param needs_implicit implicit_has_const_param
| |-MoveConstructor exists simple trivial needs_implicit
| |-CopyAssignment simple trivial has_const_param needs_implicit implicit_has_const_param
| |-MoveAssignment exists simple trivial needs_implicit
| `-Destructor simple irrelevant trivial needs_implicit
`-CXXRecordDecl <col:5, col:12> col:12 implicit struct A
The Foo::A::Foo type is missing from the AST layout, and the AST matcher does not reach it. (The test tries to find a match for Foo::A::Foo and fails).
This seems to only affect the AST. Actual codegen/behavior seems unchanged. For example:
struct Foo {
int xx;
struct A {
struct Foo {
int yy; // "yy" does not appear in AST
};
};
};
void f() {
Foo t;
t.xx = 1; // OK
t.yy = 1; // error: no member named 'yy' in 'Foo'
Foo::A::Foo z;
z.xx = 1; // error: no member named 'xx' in 'Foo::A::Foo'
z.yy = 1; // OK
}(Note: I tested this w/ #147835 plus fixes, and also at trunk. I did not test yet with #147835 alone. The regression may be due to one of the fixes instead.)